title: Corticotropin-releasing hormone (CRH) transgenic mice display hyperphagia with increased Agouti-related protein mRNA in the hypothalamic arcuate nucleus.
abstract: Although glucocorticoid-induced hyperphagia is observed in the patients with glucocorticoid treatment or Cushing's syndrome, its molecular mechanism is not clear. We thus explored the expression of neuropeptide mRNAs in the hypothalamus related to appetite regulation in CRH over-expressing transgenic mice (CRH-Tg), a model of Cushing's syndrome. We measured food intake, body weight (including body fat weight) and plasma corticosterone levels in CRH-Tg and their wild-type littermates (WT) at 6 and 14 weeks old. We also examined neuropeptide Y (NPY), proopiomelanocortin (POMC) and Agouti-related protein (AgRP) mRNAs in the arcuate nucleus (ARC) using in situ hybridization. Circulating corticosterone levels in CRH-Tg were markedly elevated at both 6 and 14 weeks old. Body fat weight in CRH-Tg was significantly increased at 14 weeks old, which is considered as an effect of chronic glucocorticoid excess. At both 6 and 14 weeks old, CRH-Tg mice showed significant hyperphagia compared with WT (14w old: WT 3.9±0.1, CRH-Tg 5.1±0.7 g/day, p<0.05). Unexpectedly, NPY mRNA levels in CRH-Tg were significantly decreased at 14 weeks old (WT: 1571.5±111.2, CRH-Tg: 949.1±139.3 dpm/mg, p<0.05), and there were no differences in POMC mRNA levels between CRH-Tg and WT. On the other hand, AgRP mRNA levels in CRH-Tg were significantly increased compared with WT at both ages (14w old: WT 365.6±88.6, CRH-Tg 660.1±87.2 dpm/ mg, p<0.05). These results suggest that glucocorticoid-induced hyperphagia is associated with increased hypothalamic AgRP. Our results also indicate that hypothalamic NPY does not have an essential role in the increased food intake during glucocorticoid excess.
authors.affiliation: Department of Endocrinology, Metabolism and Nephrology, Kochi Medical School, Kochi University, Nankoku, Japan.
authors.forename: Shuichi
authors.initials: S
authors.lastname: Nakayama
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Nishiyama
authors.forename: Yasumasa
authors.initials: Y
authors.lastname: Iwasaki
authors.forename: Masayuki
authors.initials: M
authors.lastname: Shinahara
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Okada
authors.forename: Masayuki
authors.initials: M
authors.lastname: Tsuda
authors.forename: Mizuho
authors.initials: M
authors.lastname: Okazaki
authors.forename: Makoto
authors.initials: M
authors.lastname: Tsugita
authors.forename: Takafumi
authors.initials: T
authors.lastname: Taguchi
authors.forename: Shinya
authors.initials: S
authors.lastname: Makino
authors.forename: Mary P
authors.initials: MP
authors.lastname: Stenzel-Poore
authors.forename: Kozo
authors.initials: K
authors.lastname: Hashimoto
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Terada
mesh_terms: D000273:Adipose Tissue / Q000378:metabolism; D054369:Agouti-Related Protein / Q000235:genetics*; D000818:Animals; D001111:Arcuate Nucleus of Hypothalamus / Q000378:metabolism*; D001835:Body Weight / Q000235:genetics; D003345:Corticosterone / Q000097:blood; D003346:Corticotropin-Releasing Hormone / Q000235:genetics*; D003480:Cushing Syndrome / Q000503:physiopathology; D004195:Disease Models, Animal; D004435:Eating / Q000187:drug effects / Q000235:genetics; D005938:Glucocorticoids / Q000494:pharmacology*; D006963:Hyperphagia / Q000139:chemically induced*; D008297:Male; D051379:Mice; D008822:Mice, Transgenic; D009478:Neuropeptide Y / Q000378:metabolism; D011333:Pro-Opiomelanocortin / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism
chemical_list: D054369:Agouti-Related Protein; D005938:Glucocorticoids; D009478:Neuropeptide Y; D012333:RNA, Messenger; D011333:Pro-Opiomelanocortin; D003346:Corticotropin-Releasing Hormone; D003345:Corticosterone